Computer networks have greatly enhanced the ability of people and organizations to work together through increased communications. However, this advance in communications also brings with it a greater risk of unauthorized loss of valuable information. A variety of security measures have been adopted, such as isolated or secure networks, user passwords, hardware keys, etc.
Despite security measures, an unauthorized user may gain access to a network device. This unauthorized user may seek to create a hard copy or tangible image of a file or other image on, or accessible through, the breached network device. To protect against loss of information, only authorized users should be able to generate this output. As such, it is desirable to prohibit the generation of tangible output by unauthorized users.
Tangible output in a network is generated by devices broadly known as imaging devices. Imaging devices include printers, plotters, multi-function devices and other devices used for applying an image to a tangible print media, such as paper, transparencies, card stock and more. The image is applied to the print media using a marking material, e.g., ink, ribbon, toner, or other means of applying an image to the print media.
When a tangible output image is desired, image data is converted into a form usable by the destination imaging device, often called a page description. A variety of high-level page description languages (PDLs) provide information to the imaging device on how to recreate the image. These PDLs are often device-independent languages, i.e., the same image data can be provided to devices of differing types and/or differing manufacturers to produce an end result that is substantially the same. Examples of PDLs include Printer Command Language or PCL-XL (Hewlett-Packard Company, Palo Alto, Calif., USA), PostScript® (Adobe Systems Incorporated, San Jose, Calif., USA) and Interpress (Xerox Corporation, Stamford, Conn., USA). In addition to containing data representative of the desired output image, PDLs also generally contain other information related to the control of the imaging device, e.g., what media tray to pull print media from, what resolution to use, whether the output should be in color or black and white, etc.
To process these PDLs, imaging devices have what is often referred to as a formatter. The formatter has a processor that is responsive to a control program to convert the image data to a printable image and to process the related control information. The control program typically provides interpretation of the PDLs, character generation, device emulation, interpretation of control tags and values, etc. The printable image is typically uncompressed raster or bitmap information that is supplied to another component of the imaging device, often referred to as a print engine. The print engine controls the mechanical components of the imaging device to produce the tangible output.
For the reasons stated above, and for other reasons stated below that will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for alternative methods and apparatus for secured printing in a computer network.